The Cycling Of Platinum-Group Elements And Rhenium In The Tonga Subduction Zone

汤加俯冲带铂族元素和铼的循环

• 批准号: 0117936
• 负责人: Wolfgang Bach
• 金额: $ 17.48万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-10-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0117936&HistoricalAwards=false
• 关键词: Cycling; Platinum; Group; Elements; Rhenium

AbstractThe goals of this proposed study are to better understand the behavior of platinum group elements (PGEs) during dehydration of the downgoing slab and flux melting of the mantle wedge above it. What are the parent-daughter fractionations that occur and how do these contribute to creation of mantle heterogeneities. Since the Tonga-Lau basin system is intraoceanic, the complications due to continental crust can be avoided. Analyses of Re, PGEs and Os isotopes plus 0 and S isotopes will be done for existing ODP samples from the Tonga system and old Pacific crust that have been characterized for other trace elements and isotope systems. Having a well-characterized suite of representative samples should allow an assessment of the relative contributions of subducted sediments, altered ocean crust, and the mantle wedge in arc and back arc volcanic rocks.

本研究的目的是更好地了解铂族元素在下行板块脱水和地幔楔熔融过程中的行为，它们发生了什么样的父子分馏作用，以及这些分馏作用是如何导致地幔不均匀性的。由于汤加-劳海盆系统是洋内海盆，可以避免大陆地壳造成的复杂情况。将对来自汤加系统和旧太平洋地壳的现有ODP样品进行Re、PGEs和Os同位素加上O和S同位素的分析，这些样品已被其他微量元素和同位素系统表征。有了一套特征良好的代表性样品，就可以评估俯冲沉积物、蚀变洋壳以及弧和弧后火山岩中的地幔楔的相对贡献。